/*
 * FindBugs - Find bugs in Java programs
 * Copyright (C) 2003-2005 University of Maryland
 * 
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 * 
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

package edu.umd.cs.findbugs.detect;


import java.util.HashSet;

import org.apache.bcel.classfile.Method;

import edu.umd.cs.findbugs.BugInstance;
import edu.umd.cs.findbugs.BugReporter;
import edu.umd.cs.findbugs.BytecodeScanningDetector;
import edu.umd.cs.findbugs.MethodAnnotation;
import edu.umd.cs.findbugs.StatelessDetector;
import edu.umd.cs.findbugs.ba.ClassContext;

/**
 * Detector to find private methods that are never called.
 */
public class FindUncalledPrivateMethods extends BytecodeScanningDetector implements StatelessDetector {
	private BugReporter bugReporter;
	private String className;
	private HashSet<MethodAnnotation> definedPrivateMethods, calledMethods;
	private HashSet<String> calledMethodNames;

	public FindUncalledPrivateMethods(BugReporter bugReporter) {
		this.bugReporter = bugReporter;
	}



	@Override
		 public void visitMethod(Method obj) {
		super.visitMethod(obj);
		if (obj.isPrivate()
				&& !getMethodName().equals("writeReplace")
				&& !getMethodName().equals("readResolve")
				&& !getMethodName().equals("readObject")
				&& !getMethodName().equals("readObjectNoData")
				&& !getMethodName().equals("writeObject")
				&& getMethodName().indexOf("debug") == -1
				&& getMethodName().indexOf("Debug") == -1
				&& getMethodName().indexOf("trace") == -1
				&& getMethodName().indexOf("Trace") == -1
				&& !getMethodName().equals("<init>")
				&& !getMethodName().equals("<clinit>")
		)
			definedPrivateMethods.add(MethodAnnotation.fromVisitedMethod(this));
	}

	@Override
		 public void sawOpcode(int seen) {
		switch (seen) {
		case INVOKEVIRTUAL:
		case INVOKESPECIAL:
		case INVOKESTATIC:
			if (getDottedClassConstantOperand().equals(className)) {
				String className = getDottedClassConstantOperand();
				MethodAnnotation called = new MethodAnnotation(
						className,
						getNameConstantOperand(),
						getSigConstantOperand(),
						seen == INVOKESTATIC);
				calledMethods.add(called);
				calledMethodNames.add(getNameConstantOperand().toLowerCase());
				// System.out.println("Saw call to " + called);

			}
			break;
		default:
			break;
		}
	}

	@Override
		 public void visitClassContext(ClassContext classContext) {
		definedPrivateMethods = new HashSet<MethodAnnotation>();
		calledMethods = new HashSet<MethodAnnotation>();
		calledMethodNames = new HashSet<String>();
		className = classContext.getJavaClass().getClassName();
		String[] parts = className.split("[$+.]");
		String simpleClassName = parts[parts.length - 1];
		super.visitClassContext(classContext);

		definedPrivateMethods.removeAll(calledMethods);

		for (MethodAnnotation m : definedPrivateMethods) {
			// System.out.println("Checking " + m);
			int priority = LOW_PRIORITY;
			String methodName = m.getMethodName();
			if (methodName.equals(simpleClassName) && m.getMethodSignature().equals("()V"))
				continue;
			if (methodName.length() > 1
					&& calledMethodNames.contains(methodName.toLowerCase()))
				priority = NORMAL_PRIORITY;
			BugInstance bugInstance
					= new BugInstance(this, "UPM_UNCALLED_PRIVATE_METHOD",
					priority)
					.addClass(this)
					.addMethod(m);
			bugReporter.reportBug(bugInstance);
		}

		definedPrivateMethods = null;
		calledMethods = null;
	}
}

// vim:ts=4
